ES2287468T3 - COMPOSITE MATERIAL, PROCEDURE FOR MANUFACTURING AND USE. - Google Patents

Abstract

A composite material is described that contains a reinforcing resin and reinforcing fibers, wherein the reinforcing fibers have a coating containing polyphenylene sulfide and the proportion of polyphenylene sulfide relative to the uncoated fibers is 0.001 to <0.01 wt. %. The composite material shows higher apparent interlaminar shear strength and bending strength as compared with similar composite materials having no PPS coating in the above concentration range.

Description

Composite material, procedure for Manufacturing and its use.

The invention relates to a composite material, to a procedure for its manufacture, and its use.

Reinforcement fibers and their use to make composite materials with a bonding resin are known. US 5 641 572 describes reinforcing fibers from short carbon fibers containing, as preparation, for example, phenyl polysulfide (PPS). US 5 641 572 teaches that the proportion of preparation referred to the total weight of the short carbon fibers should be at least 0.01% by weight, because with a preparation ratio less than 0.01% by weight the effect Protector is not satisfactory. Additionally, the document
US 5 641 572 teaches the carbonization of short carbon fibers glued in an inert gas at 400 to 1500 ° C. Then, the short carbon fibers contain only carbonization products of the preparation. Finally, US 5 641 572 discloses the manufacture of a reinforcing material from carbonized carbon short fibers with a thermoplastic resin. US 5 641 572 does not contain any indication on how to improve apparent intralaminar shear strength (ILSF) and flexural tear strength of composite materials containing reinforcing fibers. However, it is precisely these characteristics that are subject to increasing demands.

For this reason, the present invention arises the mission of increasing shear strength apparent intralaminar and resistance to breakage by flexion of Composite materials containing reinforcing fibers.

This mission is solved by a composite material containing a reinforcing resin and reinforcing fibers, in which the reinforcing fibers have a coating containing phenyl polysulfide, characterized in that the proportion of phenyl polysulfide with respect to the reinforcing fibers Uncoated is 0.001 to <0.01% in
weight.

If, in a manner known per se, they are incorporated reinforcing fibers coated in this way in a material compound, it is checked that the shear strength apparent intralaminar and resistance to breakage by flexion increase compared to reinforcing fibers that lack the coating according to the invention. This result must be surprising, because it was not foreseeable that such small amounts of PPS could have some influence on the properties of the composite material, much less than these few quantities in PPS weight could improve shear strength apparent intralaminar and resistance to breakage by flexion. Even more surprising is that shear strength apparent intralaminar and resistance to breakage by flexion of the composite materials according to the invention reach values peaks with a proportion of PPS in the range of 0.01 to <0.01% by weight in reinforcing fibers. This maximum value is it reaches, for example, in composite materials according to the invention, which contain coated carbon reinforcing fibers with PPS and that have been incorporated in a composite material with a polyether ether ketone, with a proportion of PPS in the carbon fibers of approximately 0.006% by weight.

In a preferred embodiment of the composite material according to the invention, the proportion of polysulfide of phenyl with respect to uncoated reinforcing fibers is from 0.002 to 0.009% by weight.

In a further preferred embodiment of the composite material according to the invention, the coating is composed of phenyl polysulfide and a thermoplastic or a duroplastic, where as a thermoplastic a polyetherimide, polyether ketone, polyether ether ketone, polyether sulfone, polyethetersulfone or polysulfone and, as duroplast, a resin epoxy.

As reinforcement resins are used in the composite material according to the invention preferably thermoplastics such as, for example, polyetherimide, polyether ketone, polyether ether ketone, polyethersulfone, polyetherether sulfone or polysulfone, or a mixture of these thermoplastics

As reinforcement fibers for the material compound according to the invention are taken into consideration, in principle, all fibers of natural or synthetic origin that they have the characteristics required of the reinforcing fibers, in where, when the reinforcing fibers are carbon based fibers in starting products of pitch, polyacrylonitrile or viscose, or aramid fibers, glass, ceramics, boron, synthetic fibers or natural fibers, or combinations of these fibers, the properties required are especially well developed. Like fibers synthetic polyether fibers are especially preferred and, as natural fibers, flax and sisal fibers.

Among the carbon reinforcing fibers are he especially prefers a carbon fiber available under the name Tenax HTS®, from the Tenax Fibers GmbH, Wuppertal (Germany), in the composite material according to the invention. In this case, the fibers may be present in the composite material according to the invention in the form of short sections or as a continuous thread, which it can be composed of many thousands, preferably by around 3,000 to 24,000 filaments. In addition, the fibers they may be present in the composite material according to the invention in the form of a flat textile product, for example, as a fabric, non-woven material, mesh fabrics, knitwear, or fit of uni- or multidirectional structures.

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The task of the invention as a basis is resolves additionally by a procedure for the manufacture of a composite material, which comprises the steps of

to)

reinforcement fiber deposit eventually pretreated,

b)

application of a layer that contains phenyl polysulfide on the reinforcing fibers of step a), so that the layer contains 0.001 to <0.01% by weight of phenyl polysulfide with respect to reinforcing fibers, so that coated reinforcing fibers are obtained, and

C)

incorporation of reinforcing fibers coated in step b) with a reinforcing resin in a material compound.

In stage a) it is basically adequate any form of deposit of the reinforcing fibers that you make accessible the entire surface of the fibers for the application of the layer in stage b). In this way, for example, Freshly spun and dry reinforcing fibers can be deposited isolated or as a fiber bundle in the manufacturing process before rolled. In the same way, reinforcing fibers can be deposit as strands of filaments, composed of many thousands of filaments, preferably around 3,000 to 24,000 filaments

In principle, for stage a) of the procedure according to the invention, fibers of reinforcement all fibers of natural or synthetic origin that satisfy the required properties of the reinforcing fibers, in where, when the reinforcing fibers are carbon fibers based on starting products of pitch, polyacrylonitrile, or viscose, or aramid, glass, ceramic, boron, or synthetic fibers or natural, or combinations of these fibers, the required properties They are especially well developed. How synthetic fibers are they prefer, in particular, polyester fibers and, as fibers natural, linen and sisal. In stage a) of the procedure according to the invention, they are deposited, especially preferably, the carbon fibers available under the Tenax HTS® name of the Tenax Fibers GmbH, Wuppertal (Germany).

The reinforcing fibers deposited in the stage a) of the process according to the invention are subjected to a pretreatment when necessary for sufficient wetting of the reinforcing fibers with the coating that is applied in the step b), and for adhesion of the coating to the fibers of reinforcement. Also, a pretreatment of reinforcing fibers it can improve the adhesion of the fibers coated with the resin of reinforcement used in step c), when the reinforcement fibers in stage b) have not been coated on its entire surface with the coating according to the invention. The procedures used to Pretreatment may eventually be procedures for impregnation, in which the reinforcing fibers are immersed in media hydrophobic or hydrophilic liquids. Additionally, they are considered pretreatment procedures in which groups are incorporated functional reagents to the surface of the fibers as, by example, electrochemical oxidation, which provides the surface of the reinforcing fibers, for example, hydroxyl groups and carboxyl.

For application in stage b) of procedure according to the invention is suitable, in principle, any procedure capable of applying on a fiber of reinforcing 0.001 to <0.01% by weight of phenyl polysulfide in relationship with reinforcing fibers.

For example, reinforcing fibers can be pass, in step b), through a PPS melt, where, optionally, the reinforcing fibers have been made pass previously through a molten mass of a thermoplastic such as, for example, polyetherimide. It is also possible prepare a melt of PPS and a thermoplastic such as, by example, polyetherimide, and pass the reinforcing fibers to through the melt of both polymers.

Alternatively, powder can be incorporated from PPS to a plasma. In this case, the PPS particles accelerate in the direction of the reinforcing fibers, and they melt. Once they have affected on the reinforcing fibers, the particles of PPS are solidify and form the desired layer on the reinforcing fiber. This plasma injection coating with PPS can go preceded by a plasma injection coating with, by example, polyetherimide. Similarly, in the coating by Plasma injection can be used simultaneously, PPS and a thermoplastic such as, for example, polyetherimide.

Additionally, the PPS application can be carry out in an integrated manner in the manufacturing process of the reinforcing fibers, before being rolled, being able to use for the application of fanned known devices. In this case, optionally before the application of PPS, you can proceed to the application of a thermoplastic such as, by example, polyetherimide. In the same way, you can manufacture a preparation of PPS and a thermoplastic such as, for example, polyetherimide, and apply this preparation on the fibers of reinforcement. In a preferred embodiment of the process according to the invention, the PPS is applied on the reinforcing fibers in the form of crystallites, where, for example, the fibers of reinforcement of stage a) is passed, in stage b), through A bath containing a suspension of PPS, dried and rolled. No special requirements are established for bath temperature, with the condition that at the selected temperature they are as thin as possible in the PPS crystallites present in the suspension. In many embodiments of the procedure according to the invention, this condition is largely fulfilled at temperature ambient, so this bath temperature is preferred. In the The drying phase is important to remove residual moisture from the coated reinforcing fibers, however, avoiding degradation of the lining. To this end, in many cases - depending on the residence time - a range of drying temperatures of approximately 350 to 400 ° C. Optionally, you can initially pass the fibers of reinforcement through a bath that contains the solution of a thermoplastic, for example, polyetherimide, then carrying the fibers soaked in this solution to a bath that contains a PPS suspension, after which the fibers are wound and dried from the way described above.

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Especially preferably, the fibers of reinforcement, which may be present, for example, in the form of thread of filaments with 3,000 to 24,000 filaments, are passed to through a bathroom whose content is composed of a suspension of PPS, a thermoplastic solution, for example, a solution of polyetherimide, a solvent and, eventually, also a emulsifier, after which the fibers are dried and rolled over mode described above. The solvent is selected so that the PPS does not dissolve, but the thermoplastics. For this one objective, when the thermoplastic is polyetherimide, it turns out appropriate for example 1-methyl-2-pyrrolidone (NMP) As an emulsifier, for example, ethyl ether is suitable of decaethylene glycol. In this case and in all forms of embodiment of the process according to the invention in which use a PPS suspension in a bathroom, the suspension status it is maintained by the constant movement of the content of said bath, for example, by transfer by pumping or agitation. When doing pass the reinforcing fibers through the bath, the thread tension it is preferably from 0.3 to 1.5 cN / tex and, so Especially preferred, from 0.5 to 1.0 cN / tex. Speed at that the reinforcing fibers are passed through the suspension is, preferably, from 60 to 600 m / h and, especially preferred, from 120 to 480 m / h. Suspension concentration PPS in the bath is preferably 0.2 to 5% by weight and, of especially preferred form, 0.5 to 1.5% by weight of PPS, in relationship always with the content of polyetherimide, whose proportion by weight in the content of the bathroom is within the range 0.5 to 1.0% by weight and, especially preferably, within the range of 0.5 to 0.7% by weight. Parameters above mentioned are coordinated so that on the reinforcing fibers apply, for example, a coating of 0.5 up to 1.0% by weight and, especially preferably, 0.5 up to 0.7% by weight.

A suspension with crystallites especially Fine PPS has the possibility, when thermoplastic and PPS are incorporated in an extruder in the proportions by weight previously mentioned, to melt in the extruder and form a granulated. This granulate is incorporated into the solvent mentioned above. which eventually contains an emulsifier. In this way, the thermoplastic dissolves and the PPS forms a suspension of fine particles The proportion of PPS according to the invention over the reinforcing fibers can be adjusted, for example, by setting the PPS concentration in the bathroom so that, at a speed of predetermined advance of the reinforcing fibers through the bath, coated reinforcing fibers contain 0.001 to <0.01% by weight of PPS.

The proportion by weight of the coating in the Reinforcement fibers are determined according to DIN EN ISO 10548, Method B. In case the fiber coating contains, In addition to PPS, a thermoplastic, the weight ratio of PPS in Coated reinforcing fibers are calculated from the ratio by weight of the thermoplastic to PPS used for the coating.

In step c) of the procedure according to invention, the coated reinforcing fibers are processed with a reinforcing resin, preferably with a thermoplastic or a thermoplastic mixture to give a composite material. In this In this case, as a thermoplastic, especially a polyetherimide, polyether ketone, polyether ether ketone, polyether sulfone, polyetherether sulfone or polysulfone, or a mixture of these thermoplastics The procedures by which the fibers Coated reinforcement according to the invention are processed to form Composite materials are known as such. They belong to these, for example

-

mixture of the reinforcing fibers coated according to the invention with fibers or with a powder, or with a sheet of a bonding resin and subsequent heat pressed,

-

impregnation of reinforcing fibers coated according to the invention with a melt or solution of the bonding resin, and

-

formation of a composition ("compound") of the coated reinforcing fibers, cut to short fiber dimensions.

In this case, the coated reinforcing fibers according to the invention they can continue processing in their configuration to form a composite material, where they are present according to step b) of the process according to the invention, for example, as a filament thread.

Alternatively, reinforcing fibers coated, resulting from step b) of the process according to invention, initially, can be brought to a configuration of a flat textile structure and, already in this configuration, process them to give a composite material. For example, the fibers of reinforcement resulting from step b) of the process according to the invention can be processed firstly to form a non-woven material, or cut them to create short fibers. Of the same Thus, the coated reinforcing fibers according to the invention are they can lead, first, to the configuration of a tissue, mesh gender, knitwear, or in the configuration of a uni- or multidirectional structure.

In the manufacture of the composite material in the step c), the coated reinforcing fibers according to the invention exhibit excellent impregnation behavior in pressing with heat with polyether ketone, as well as with respect to penetration of the polyether ketone in the filament thread, and also in relation to the wetting of the coated filaments individually.

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The composite materials according to the invention they have a fiber volume ratio of 40 to 70% in volume, where the proportion by volume of fibers in laminates of Unidirectional prepreg products are found, preferably, in the range of 55 to 65% by volume, in laminates of prepreg tissue products, in the range of 45 to 55% by volume, and in the bodies rolled or processed by pultrusion, they are in the range of 55 to 70% in weigh.

In the composite materials according to the invention the apparent shear strength is measured according to the Standard DIN EN 2563, and resistance to breakage by flexion (0º in fiber direction and 90º perpendicular to the direction of the fibers), according to DIN EN 2562.

The composite material according to the invention and the composite material manufactured according to the procedure according to the invention can be used, advantageously, for the manufacture of components for the construction of aircraft such such as the belly of the fuselage and landing wings, in the construction of cars such as, for example, parts of the engine, pumps and seals, in the construction of machines and facilities such as, for example, gaskets, warehouses and containers, and in the manufacture of medical components such as, For example, surgical instruments.

The invention will be explained in more detail. by the following examples.

Example 1

98 parts by weight are incorporated in an extruder polyetherimide (Ultem® from GE-Plastics Company) and 2 parts by weight of PPS (Fortron® of the Ticona Company), is they melt in the extruder, and a granulate is made. 39 g of granules are mixed with stirring with 590 g of 1-methyl-2-pyrrolidone (NMP) hot, until the dissolution of the polyetherimide. PPS does not It dissolves and forms a suspension. To the polyetherimide solution, or to the PPS suspension, stirred and cooled to 70 ° C is added, drop dropwise, a mixture consisting of 200 g of NMP, 60 g of water and 20 g of the ethylene ether emulsifier of decaethylene glycol. Mix The resulting mixture is mixed with stirring in 600 ml of water heated to 50 ° C, so that an emulsion is formed that stays in constant movement by pumping transfer. The solution obtained in this way is diluted until a solution is reached composed of 0.6% by weight of polyetherimide, 0.006% by weight of PPS, 0.3% by weight of ethyl ether of decaethylene glycol, 12.2% by weight of NMP, and 86.894% by weight of water.

A filament thread, with a title of 800 tex, formed by carbon fibers, available for the name Tenax HTS® in the Tenax Fibers GmbH Company, pretreated by electrochemical oxidation, is passed with a wire tension of 1.0 cN / tex and a speed of 180 m / h through the emulsion described above, dried at 350 ° C and rolled. The proportion of PPS with respect to carbon fibers amounts to 0.006% by weight (see Table,
Example 1).

The filament thread is processed with polyetheretherketone, available under the name PEEK® 151G in the Victrex® company, to form a composite material. In this case, The polyether ether ketone is used in sheet form. They form alternating deposits of this sheet and Tenax HTS® fibers coated. Subsequently, alternating deposits are compressed at a pressure of approx. 9 bar and at a slightly higher temperature than 400 ° C. After compression, the material temperature compound is reduced, within 24 hours, at temperature ambient.

The resistance to intralaminar shear Apparent is 143 MPa, the resistance to breakage by bending (0 ° C) is 3380.4 MPa, and the resistance to breakage by bending (90 ° C) is 187 MPa (see Table, Example 1).

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Example 2

Example 1 is repeated, with the difference that the emulsion is composed of 0.597% by weight of polyetherimide, 0.009% by weight of PPS, 0.3% by weight of ethyl ether of decaethylene glycol, 12.2% by weight of NMP , and 86.894% by weight of water. The proportion of PPS with respect to carbon fibers is 0.009% by weight (see Table,
Example 2).

The resistance to intralaminar shear is of 125 MPa, the resistance to breakage by flexion (0ºC) is 2927.1 MPa, and the resistance to breakage by flexion (90 ° C) is 153 MPa (see Table, Example 2).

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Example Comparative

Example 1 is repeated, with the difference that The emulsion does not contain PPS and is composed of 0.606% by weight of polyetherimide, 0.3% by weight of ethyl ether of decaethylene glycol, 12.2% by weight of NMP, and 86.894% by weight of water (see Table, Comparative example V).

The resistance to intralaminar shear Apparent is 121 MPa, the resistance to breakage by bending (0 ° C) is 2473.3 MPa, and the resistance to breakage by bending (90 ° C) is 152 MPa (see Table, Comparative Example V).

The table summarizes the percentages by weight of PPS, referring to carbon fibers (% by weight of PPS), the intralaminar shear strength (ILSF), resistance to flexural breakage (0º) as BBF (0º) and resistance to flexural breakage (90º) as BBF (90º).

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one

From the Table, it is recognized that the ILSF and the BBF at 0º and 90º reach maximum values with a proportion of PPS in carbon fibers of 0.006% by weight.

Claims (16)

1. Composite material containing a reinforcing resin and reinforcing fibers, in which the reinforcing fibers have a coating containing phenyl polysulphide, characterized in that the proportion of phenyl polysulfide with respect to the uncoated reinforcing fibers is 0.001 to <0.01% by weight. 2. Composite material according to claim 1, characterized in that the proportion of phenyl polysulphide with respect to the uncoated reinforcing fibers is from 0.002 to 0.009% by weight. 3. Composite material according to claim 1 or 2, characterized in that the coating is composed of phenyl polysulfide and a thermoplastic or duroplastic. 4. Composite material according to one or multiple claims 1 to 3, characterized in that the reinforcing resin is a thermoplastic or a mixture of thermoplastics. 5. Composite material according to one or multiple claims 1 to 4, characterized in that the reinforcing fibers are carbon fibers of pitch, polyacrylonitrile or viscose starting products, aramid fibers, glass fibers, ceramic fibers, boron fibers, synthetic fibers or natural fibers, or combinations of these fibers. 6. Procedure for the manufacture of a composite material comprising the steps of

to)

reinforcement fiber tank, eventually pretreated,

b)

application of a layer that contains phenyl polysulfide on the reinforcing fibers of step a), so that the layer contains 0.001 to <0.01% by weight of phenyl polysulfide with respect to reinforcing fibers, whereby coated reinforcing fibers are obtained, Y

C)

Processing of reinforcement fibers coated in step b) with a reinforcing resin, to give a composite material.

Method according to claim 6, characterized in that the reinforcing fibers of step a) are carbon fibers of pitch, polyacrylonitrile or viscose starting products, aramid fibers, glass fibers, ceramic fibers, boron fibers, synthetic fibers or natural fibers, or combinations of these fibers. Method according to claim 6 or 7, characterized in that the carbon reinforcing fibers of step a) have been pretreated by electrochemical oxidation. Method according to one or multiple claims 6 to 8, characterized in that the reinforcing fibers of step a) are passed, in step b), through a bath containing a suspension of phenyl polysulfide, they are dried and They roll over. Method according to claim 9, characterized in that the bath additionally contains a solution of a thermoplastic. 11. Method according to one or multiple claims 6 to 10, characterized in that the reinforcing fibers coated in step c) are processed in the configuration of filament yarns, short fibers, fabrics, mesh fabrics, knitwear, nonwoven materials , uni- or multidirectional structures to give a composite material. 12. Use of composite material according to one or multiple claims 1 to 5, or of a composite material manufactured according to one or multiple claims 6 to 11, for manufacture components for aircraft construction, car construction, machine building e facilities, and to manufacture medical components. 13. Reinforcement fibers, having a coating containing phenyl polysulphide, characterized in that the proportion of phenyl polysulfide with respect to uncoated reinforcing fibers is from 0.001 to <0.01% by weight. 14. Reinforcing fibers according to claim 13, characterized in that the proportion of phenyl polysulphide with respect to uncoated reinforcing fibers is 0.002 to 0.009% by weight. 15. Reinforcing fibers according to claim 13 or 14, characterized in that the coating is composed of phenyl polysulfide and a thermoplastic or duroplast. 16. Reinforcing fibers according to one or multiple claims 13 to 15, characterized in that the reinforcing fibers are carbon fibers of pitch, polyacrylonitrile or viscose starting products, aramid fibers, glass fibers, ceramic fibers, boron fibers , synthetic fibers or natural fibers, or combinations of these fibers.